The present invention relates to a system for intravaginal delivery of drugs and other substances, including but not limited to spermicides, germicides, virucides, medicants, anti-infection agents, hormones, deodorizing materials, lubricants, steroids, anti-bacterial agents, and other pharmacological agents, chemical, natural, or homeopathic agents, and anesthetics. The invention also relates to an improved device for reliably, comfortably and conveniently introducing drugs and/or other substances into the vagina.
The prior art has failed to provide a satisfactory system for delivering drugs and other substances to the vagina. Among other things, the prior art has failed to provide an effective intravaginal drug delivery device that can be economically mass produced, easily handled, and worn comfortably within the vagina. Although a number of contraceptive devices have been designed to deliver spermicidal substances and other active agents, such prior art devices are all unsatisfactory, for a variety of reasons.
U.S. Pat. No. 4,785,804 (Tlapek), for example, refers to a disposable cervical cap which is pre-treated with nonoxvl-9 or other spermicides. The Tlapek device has a thin flexible dome and an integral rim. The rim has an inwardly directed annular groove for gripping the cervix wall to keep the cap in position. In the Tlapek device, the dome and the rim provide a contraceptive barrier, and the spermicide is used to increase the contraceptive effect. An integrally molded loop is provided to remove the cervical cap. According to Tlapek, a string, ring or tab could also be used to remove the device from the vagina. The Tlapek cap is unsatisfactory because among other things it requires a removal device which increases its complexity and cost of manufacture. In addition, the Tlapek device may be difficult to locate and remove from its installed position gripping the cervix, and the manner in which its annular groove is located snugly over the cervix may cause discomfort in some users.
U.S. Pat. No. 4,526,578 (Wong) discloses another disposable device for delivering spermicide. The Wong device is in the form of a dome-shaped occlusive diaphragm that fits snugly within the vagina, covering the cervix and part of the anterior vaginal wall. The prior art Wong diaphragm has an annular reservoir formed of porous material. Spermicide is located within the porous reservoir. A film structure is integrally formed with the annular reservoir. According to Wong, the film structure may also incorporate spermicide. The active spermicidal agent may be added to the film structure during its formation.
The Wong device has several disadvantages. First, its annular reservoir would be complex and difficult to produce economically. Moreover, the diaphragm-shaped device would be difficult to collapse and insert by hand into the vagina. The annular reservoir has a circular cross-section and consequently would tend to twist if diametrically opposite portions were pinched toward each other. Moreover, the reservoir would tend to slip out from between the user's fingertips. Another problem with the Wong device is that its film material could not be relied upon to fold into a narrow, low-profile configuration for convenient, comfortable insertion. Moreover, the snug internal fit for which the Wong device is designed could cause discomfort with some users.
U.S. Pat. No. 5,044,376 (Shields) discloses a contraceptive diaphragm. The device has a tensioning spring and a receptacle for receiving a foam pad. The pad contains spermicide that is released by diffusion into the vagina. A retaining ring is provided for holding the pad in place. The pad and the retaining ring add complexity to the Shields device and would make it relatively difficult to manufacture. Another disadvantage of the Shields device is that it would not be easily compressible into a low profile configuration for insertion. In particular, the device could not be compressed into a figure-eight-shaped configuration with the pad substantially located within the spring. Moreover, the Shields device is generally bulky and does not appear to have been designed for comfort. Shields also discloses a drug delivery device in the form of a cervical cap.
U.S. Pat. No. 4,822,616 (Zimmermann) discloses a vaginal ring for time-released introduction of steroid hormones. The Zimmermann ring is formed of injection molded silicone elastomer. The cross-section of the ring is kidney-shaped. The Zimmermann ring is formed in several layers. This complex, multi-layer construction would make it relatively difficult and expensive to manufacture. Moreover, the ring's flat profile would be difficult to handle. The height of the ring is less than its thickness. Therefore, it would be relatively difficult to compress the ring into a figure-eight-shaped position for insertion. The ring would tend to twist and slip out from between the user's fingers. Another disadvantage of the Zimmermann ring is that it does not appear to have been designed for comfort. Moreover, the prior art ring has no film covering its central open space. Consequently, the Zimmermann device has reduced surface area available for delivering drugs or any other substances, and the Zimmermann device could not be used to collect or contain fluid.
Other prior art systems for delivering substances into the vagina are shown by U.S. Pat. No. 4,630,602 (Strickman), U.S. Pat. No. 4,589,880 (Dunn), U.S. Pat. No. 4,553,972 (Vickery), U.S. Pat. No. 4,311,543 (Strickman '543), U.S. Pat. No. 4,286,587 (Wong '587), U.S. Pat. No. 4,219,016 (Drobish), U.S. Pat. No. 4,198,976 (Drobish '976), U.S. Pat. No. 3,854,480 (Zaffaroni), and British Patents Nos. 260,600 (Fiessler) and 21,588 (Fickert).